This application contains a computer program listing appendix submitted on compact discs and incorporated herein by reference. Said computer program listing appendix is contained in a single file having the name xe2x80x9cprogramming code appendix,xe2x80x9d created Apr. 25, 2001, and having a size of 18,000 bytes. Said computer program listing is submitted in duplicate (two discs).
1. The Field of the Invention
This invention generally relates to apparatus used in connection with underwater diving equipment. More particularly, the present invention relates to equipment used to apprise an underwater diver of important information needed to efficiently use diving time and to maintain safe diving conditions.
2. The Background Art
The introduction of underwater diving using Self-Contained Underwater Breathing Apparatus (SCUBA) in the 1940""s by Jacques-Yves Cousteau and Emil Gagnan opened up new possibilities in underwater exploration. Today, scuba diving is a very popular sport as well as an indispensable professional activity. It is estimated that more than 3,000,000 divers are currently xe2x80x9copen waterxe2x80x9d certified and that another 600,000 new divers are certified worldwide each year. Thus, diving is expected to become more widespread both as a recreational activity and as a professional endeavor.
Regardless of the expansion of diving, it is considered by many to be an inherently dangerous activity. Thus, safe diving practice as well as the science and physiology of diving are taught as part of the open water certification process. Safety procedures and practices are continually being emphasized by manufacturers, educators, and participants in the industry.
In order to allow the recreational diver to participate in the sport both safely and enjoyably, it is imperative that the diver be apprised of environmental conditions during the dive as well as the status of the diving equipment. Such environmental conditions and equipment status include the elapsed time of the dive and the maximum depth of the dive and the time spent at the maximum depth. It is also important to keep an accurate log of each dive made in the recent past so that repetitive dives over a period of time can be safely performed.
While underwater diving has many hazards, one of the hazards which can be managed is decompression sickness (DCS), commonly known as the xe2x80x9cbends.xe2x80x9d DCS comes about because inert gases (principally nitrogen, which is the major constituent of air compressed into the air tanks of most divers), are absorbed into the blood and tissues of a diver during a dive. The greater the depth of the dive (i.e., the greater the ambient pressure on the diver) and the length of the dive, the greater the amount of nitrogen which is absorbed into the diver""s blood and tissues. If the diver rapidly returns to a shallower depth, or to the surface, the decrease in ambient pressure causes the nitrogen to be deabsorbed and harmful bubbles form in the tissue and blood.
The process of absorption and deabsorption of nitrogen into the blood and tissues is governed by Boyles Law and the fact that the partial pressures of inert gases (principally nitrogen), increases as the diver proceeds deeper into the dive. This causes a disequilibrium between the inert gases in the blood, fluids, and tissues of the diver""s body and the air mixture being inhaled. This disequilibrium causes more of the inert gases to be absorbed by the body of the diver. Upon assent to the surface the ambient pressure is reduced and the disequilibrium is again created. This time however, excess gases are deabsorbed by the body fluids and tissues into the air mixture being exhaled. If the dissolved gases are released too quickly they form bubbles in the blood, fluids, joints, and other tissues of the diver""s body which can cause problems ranging from minor discomfort to death.
DCS can be controlled by monitoring dive conditions, limiting dive depth and the length of the dive, and controlling the assent rate to the surface. Nevertheless, due to human nature and other realities of diving, divers occasionally encounter DCS because of miscalculations or misjudgments.
Potential problems with DCS exist in every dive and are dealt with by educating the diver about safe dive depths, dive times, and assent rates. Such variables can be very roughly manually calculated using dive tables, for example those provided by the U.S. Navy and other organizations, to determine the safe rate of assent from a maximum depth in conjunction with the time spent at that maximum depth. Importantly, both professional and recreational divers require accurate information about the parameters of their dives so that diving time and the depths can be maximized.
In order to give the diver the information needed to plan and control a safe dive, a diver is now often equipped with underwater stop watches, conventional magnetic compasses, analog scuba tank pressure gauges, and depth gauges, as well as, on occasion, a thermometer. Recently, carry-along dive computers, which monitor various environmental and equipment sensors and perform dive table type calculations, have been available to provide important information to a diver during the course of the dive.
Provided in FIG. 1 is a representation of a diver, generally indicated at 10, using one of several previously available carry-along dive computers. In the arrangement illustrated in FIG. 1, the dive computer console 18, which includes gauges or indicators 19, is connected to a scuba air tank 12 by way of a high pressure hose 20 which communicates the pressure within the scuba air tank 12 to the dive computer console 18. The diver 10 receives air from the tank 12 via a conventional mouth piece 14 connected to the tank by a low pressure hose (not represented).
In the arrangement represented in FIG. 1, the dive computer console 18 hangs down behind the diver 10, traditionally on the left side of the diver. In some instances, the dive computer console is held in the diver""s hand or is attached to the diver""s arm.
One readily recognized problem with the arrangement for a dive computer shown in FIG. 1 is that the diver must reach for, and grasp, the dive computer console 18 and bring it into his field of view each time the gauges or indicators 19 are to be checked. Because the diver 10 must make a conscious effort to reach for the dive computer console 18 and bring it into his field of view, it is less likely that the diver 10 will check the gauges or indicators 19 as often as is desirable due to environmental distractions or due to a task at hand. Also, because it is not easy to find and grasp the dive computer console 18, in a panic moment or critical situation the diver may be unable to quickly grasp it and/or bring it into his field of view.
Moreover, the arrangement using a dive computer console 18 attached to the tank 12 via a high pressure hose 20 poses the safety risk of the high pressure hose 20 or dive computer console 18 snagging or catching on underwater objects such as coral. The dangers posed by rupturing the high pressure hose 20 are readily evident.
Additionally, in murky or turbid water it may be impossible to observe the gauges or indicators 19 unless they are placed against the viewing window of the diving mask 16. This requires the diver 10 to divert his attention from the task at hand on a regular basis or from a dive buddy (companion) which the diver 10 should be continuously observing in order to ensure the dive buddy""s safety. Moreover, when divers are exploring coral reefs constant attention should be paid to avoiding contact with the reef; both unintentional and intentional contact by divers is rapidly causing the destruction of many coral reefs in the world.
Because of these and other drawbacks and problems encountered in the present state of the art, it would be a great advance in the art to provide a dive computer which overcomes these disadvantages by providing safer and more efficient underwater diving.
In view of the above described state of the art, the present invention seeks to realize the following objects and advantages.
It is a primary object of the present invention to provide a dive computer system which conveys important information to a diver in a more safe and efficient manner than previously available devices.
It is also a significant object of the present invention to provide a dive computer system which efficiently conveys important information to the diver without diverting the diver""s attention away from the surrounding environment.
It is another object of the present invention to provide a dive computer system which can provide information to the diver directly in front of the diver""s eye and always within the diver""s field of view which does not block the diver""s view of the surrounding environment.
It is a further object of the present invention to provide a dive computer which does not present any hazardous high pressure hoses or consoles which can snag on underwater objects and formations or become entangled with the diver""s other equipment.
It is another object of the present invention to provide a dive computer which does not present any additional dangers to a diver such as the rupturing of a high pressure hose or severing of an electrical cable.
It is still another object of the present invention to provide a dive computer system which includes a compass function and which provides hands-free operation and which operates reliably when the diver is positioned in any of a number of orientations.
It is also an object of the present invention to provide a dive computer which provides long operating time without changing or recharging batteries.
It is a further object of the present invention to provide a dive computer system which presents continuously updated information within the diver""s field of view and which can accommodate a variety of eyesight parameters, facial structures, and eye shapes and sizes.
It is yet another object of the present invention to provide a dive computer which projects the image onto the diver""s field of view and which does not block any of the diver""s view of the surrounding environment.
It is another object of the present invention to provide a field of view display which can be used in association with a variety of different types of masks so that information can be conveyed to the user without requiring the user to make any head movements or hand movements.
Another object of the present invention is to provide a field of view display which can be integrally formed in a mask or retrofit onto an existing mask.
These and other objects and advantages of the invention will become more fully apparent from the description and claims which follow, or may be learned by the practice of the invention.
The present invention provides a great advance in the art pertaining to devices and systems used to improve the efficiency and safety of underwater diving as well as providing an improved system for conveying information to users wearing a mask over their eyes. The present invention is primarily intended to be used as a system for conveying information to an underwater diver wearing a mask but can also be used in other applications.
The present invention keeps an underwater diver informed of important information during a dive without requiring the diver to divert his attention from the surrounding environment. Underwater divers generally wear a mask which includes a viewing window or lens through which the diver is provided a field of view of the surrounding environment.
The preferred embodiments of the present invention include a means for sensing the pressure in at least one tank, holding a breathable gas supplied to the diver, and for generating a tank pressure signal. Also included is a means for sensing the depth under the surface of the water the diver is submerged. The means for sensing the depth also generates a depth signal. Additionally, a means for processing the tank pressure signal and the depth signal is included. The means for processing generates a display signal which contains information which is to be conveyed to the diver. The means for processing preferably comprises a microcomputer and its associated signal processing circuitry.
A means for displaying the information conveyed by the display signal within the diver""s field of view is also provided. The means for displaying is arranged such that the diver is able to visually perceive the information without any movement, or only a slight movement, of an eye and without any need to substantially refocus eyesight within the field of view. Desirably, a means for holding the means for displaying in a position on the mask is provided. Thus, the diver or other user is apprised of important information without moving his head or hands.
The means for displaying can desirably include a visual array means for providing a visually perceptible representation of the information conveyed by the display signal. The means for displaying preferably also includes a means for placing an image of the visual array means at a focus distance in the range from about six feet to about infinity, and most preferably in the range from about three feet to about infinity, in relation to the eye of the diver, as well as, a means for magnifying the actual image of the visual array means such that the diver can readily observe the image of the visual array means.
The structures of the means for displaying, or the field of view system, can be carried out using lenses, mirrors, and/or other conventional or holographic optical components. Such optical components can include lenses, combiners, prisms, various lens coatings designed to affect and control transmission and reflectively of individual components and other optical components, both those currently available and those which may become available in the future. Since a user of the present invention may often be found in an environment where there is little or no ambient light, some embodiments may include means for providing light on the display in the case of displays which are not self illuminating. Significantly, the embodiments of the present invention can be configured integrally with a mask or other components or, alternatively, can be added to existing components, e.q., masks and tanks, as a retrofit.
Also included in some preferred embodiments of the present invention is a means for detecting changes in the relative orientation of the earth""s magnetic field and generating a compass signal with respect to its orientation in the earth""s magnetic field. The compass signal is also processed by the means for processing and presented to the diver as an image within the diver""s field of view.
Preferably, the means for detecting changes in the relative orientation in the earth""s magnetic field comprises a fluxgate compass device. Other devices, both those now available and which become available in the future, can also be used within the scope of the present invention as a compass sensor. In order to allow the compass sensor to properly operate in a diving environment, it is preferred in some embodiments of the present invention to provide a means for maintaining the compass device in substantially the same orientation in one (horizontal) plane. The means for maintaining the compass device in substantially the same orientation desirably can include suspending the compass sensor in a liquid to dampen transient movements. Also, embodiments of the present invention can further include arrangements, either in the form of hardware or software, which reduce or eliminate the need to maintain the compass sensor in the same physical orientation.
The display means can desirably include a light emitting diode array, a liquid crystal display (preferably with supplemental illumination), or some other solid state array device. In most preferred embodiments, many of the sensors will be positioned remotely from the means for displaying and an optical link, such as a fiber optic cable which is inherently safer and more reliable in an underwater environment than electrical cables, is provided to convey signals between the components.
The preferred embodiments of the present invention also can include means for sensing the ambient temperature of the surrounding environment. The means for sensing the ambient temperature generates a temperature signal that can be visually represented on the means for displaying. A means for conveying audio messages to the diver can also be provided. The means for displaying can also include: means for displaying the temperature of the water surrounding the diver; means for displaying the minimum temperature of the water encountered on the most recent dive; means for displaying the current depth of the diver under the surface of the water; means for displaying the maximum depth under the surface of the water encountered on the most recent dive; structures for displaying the current pressure found within the tank; structures for displaying the elapsed time since the beginning of the most recent dive; as well as, means for calculating and displaying the time remaining before a diver must ascend, means for calculating and displaying to the diver a plurality of ascent stop level needed to avoid DCS, and means for calculating and displaying the diver""s ascent rate.
As will be appreciated, the present invention includes combinations of features and structures heretofore unknown and not suggested in the available pertinent art. The present invention solves problems which have been unrecognized and/or unsolved for a long time.